Summary:
While trying to use QuickBooks Integration Manager with Web Timesheet, the Client Invoices option is missing. The version of Integration manager is 5.5.

Resolution:
This issue is occurring because the 'Client Invoice' option is not enabled in the Quick Book Integration Manager. Please find the steps below to enable this option:

Open QuickBooks and then open the QuickBooks integration Manager.
Click on the option called Wizards in the QuickBooks integration Manager.
Put a check in the box beside Client Invoice and click on Save.

Note:
This will enable the time and expenses sub option to Client Invoice. If any of these two option is not required, it can be unchecked and disabled accordingly.